A friend told me how to find the Köhler's Violin Repository books on
archive.org, which I hadn't found due to the serious typo in the name. The software not only dropped the 'ö' (o-umlaut), but also lost the 'h', producing a title "Klers' violin repository of dance music". This prevents search sites like google from finding it, and
archive.org's search tools also fail. The file names have the same problem; they start with "klers", which doesn't match "kohler" or "köhler". The software can handle umlauted letters, since other books with the name "Köhler" in the title or author fields are found.
Also, there's a bad page in book 2 ("klersviolinrepos02rugg"): Köhlers' page 190 (
archive.org's page 102) in the PDF version comes up as a nearly blank page, with a few dots and smudges, but no image of the music. The other pages all seem to be fine; it's just this one page that can't be read. This is the black-and-white PDF, klersviolinrepos02rugg_
bw.pdf; I haven't yet downloaded the "color" PDF. I tried it with several program (on my Macbook Pro) that display PDF, such as Preview, Safari and Chrome, and all show that one page as dots and smudges with no music. The "online" version shows the page correctly.